How much do you know about drill tail screws

Self Tapping screws: mechanical performance requirements
Heart hardness: standard value HRC28-38. When testing, take a cross-section that is 1-2 times the diameter of the tail for measurement. If the length of the measurement is too short, it can be embedded first and then tested for hardness
Surface hardness: Standard MINHV450
Carbonized layer: Standard 4 # -6 #: 0.05-0.18mm, 8 # -12 #: 0.10-0.23mm, 14 #: 0.13_0.28mm. The main purpose of carburization is to enhance surface hardness and ensure the strength of teeth. If the decarburization is too deep and the carburization is insufficient, the strength of the teeth will not meet the requirements, which means that the teeth will be damaged during the screw in test